Tapping bar assembly

ABSTRACT

A tapping bar assembly is set forth, which serves to eliminate discarding of scrap lengths of bar. The assembly includes at least a pair of generally cylindrical tapping bars, which are held in rigid end-to-end relationship by a consumable metallic sleeve surrounding the adjoining bar ends and crimped thereabout.

United States Patent Inventor Wllllam J. Bernnt [56] References Clted A I N (zlgasesston, S.C. UNITED STATES PATENTS PP v Filed p 1,1970 2,432,996 l2/l947 Larson et al. 266/42 Patented Nov. 9, 1971 Primary Examiner-Gerald A. Dost Assignee All Reduction Company, Incorporated Auorneys- Riggs T. Stewart, Edmund W. Bopp and H. Hume New York, N.Y. Mathews TAPPING BAR ASSEMBLY 8 2 Dnwlng Figs ABSTRACT: A tapping bar assembly is set forth, which serves U.S. Cl 266/42, to eliminate discarding of scrap lengths of bar. The assembly 266/ l R includes at least a pair of generally cylindrical tapping bars, Int. Cl C21b 7/12 which are held in rigid end-to-end relationship by a consuma- Fleld of Search 266/! R, l ble metallic sleeve surrounding the adjoining bar ends and S, 42; 13/! 33, 35, crimped thereabout.

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PATENTEDNBV 9l97| 3,618,926

INVENTOR WILLIAM J. BERNAT BY 2 i 32 A ORNEY TAPPING BAR ASSEMBLY BACKGROUND OF THE INVENTION This invention relates generally to metallurgical furnaces and more specifically to apparatus useful for tapping these furnaces.

In the course of operating various metallurgical'fumaces, such as the submerged are variety, the furnace is periodically tapped to remove the molten metallurgical product. This is commonly achieved by removing a clay plug from the tap opening in the lower furnace wall. The plug is normally inserted into the furnace in a plastic condition while the furnace is at a low level. During the smelting process, the clay hardens tov form a fairly rigid seal, and accordingly breach of the hardened plug must be effected by applying a degree of posi tive force. Typically, therefore, the plug is removed or broken by impacting the plug material with the end of a narrow metal bar to the plug by an operator at a required safe distance from the dangerous environment of the furnace.

The bars referred to are known in the industry as tapping bars" and usually comprise of a metallic material which is compatible with the metallurgical product in the furnace as they will penetrate the plug and be partially consumed in the melt. Since the operator while manipulating a bar must maintain a safe distance from the furnace, the bar length must, at a minimum, equal a safe approach distance for the operator. Furthermore, a portion of bar isconsumed each timea tap is made and a typical new bar should be feet, or more, in length to enable multiple use of the bar.

The cited safe approach distance for a tapping operator is usually no less than 6 feet and, in practice, this requires that the tapping bar not only be of at least this length, but of .such mechanical strength that a portion can be effectively cantilevered over this minimum distance and still be brought to bear onthe tap plug. As continueduse brings the length of tapping bars to correspond with the cited minimum operator approach distance, it has been customary in the past to scrap the shortened lengths substituting an entirely new bar. In view of the enormous quantity of such bars used in the metal smelting industry, this practice has represented an excessive waste of material resulting in extremely high cost to the industry.

oanscrs OF THE ruvssmolv In view of the foregoing, it should be regarded that an object of the present invention is to provide a tapping bar assembly which eliminates discarding reduced bar lengths, thereby effecting economies in the industry.

It is a further object of the invention to provide a tapping bar assembly which enables effective joining of lengths of bar previously considered unusable, being of such simplicity and ease of formation that it may be readily used on the production line.

It is a still further object of the present invention, to provide a tapping bar assembly of simplicity and ease of construction, which results in a sufiiciently rigid structure so that bars de pending therefrom can be safely cantilevered over the minimum operator approach distance to the furnace and brought to bear on the tap plug.

It is another object of the invention, to provide a method of utilization of tapping bars which obviates the prior wasteful practice of discarding bar lengths falling below the minimum safe distance of approach for an operator in the vicinity of a tapped furnace.

SUMMARY OF INVENTION Now, in accordance with the present invention, the foregoing objects and others as will become apparent in the ensuing specification, are achieved by means of a tapping bar assembly utilizing an extended metallic sleeve to rigidly couple a pair of cylindrical tapping bars in end to end relationship. The sleeve, comprising a material which is consumable in the furnace without noxious effects upon the furnace or melt, may, for example, consist of a pipe length which is crimped about the bars after insertion of the bar ends. Since the minimum length of scrap bars joined will be that of the minimum safe operator approach distance to the furnace, the said sleeve is of sufficient length as to be able to support in a cantilevered manner at least bar lengths of such dimensions depending from the assembly.

BRIEF DESCRIPTION OF DRAWINGS which certain forcesare generated within a joined bar length.

DESCRIPTION OF PREFERRED EMBODIMENT FIG.) shows a longitudinal cross section of an assembly in the process of formation, in accordance with the invention. As can be seen, the assembly 2 includes a pair of tapping bars 3 and 5, which are in end to end abutment at point 4 within the surrounding sleeve 7. The bar} is typically a remnant scrap length which, in particular, has been derived from an original tapping bar having a continuous new. length of 20 feet or more. Typically such original bars are some 20 to 22.feet in length, of about I inch in diameter, and are made of amate'rial whichis completely compatible with the furnace melt, i.e."the

' bars are consumable in the furnace without detrimental effect to either furnace or contained melt. Thus, in a typical submerged-arc furnace, such bars will comprise ordinary carbon steel, e.g. AISI 1010 or AISI I020 carbon steel, although the exactcompositionis in no way critical and it may be formed of any convenient material of sufficient strength for the purpose. The bar 3 will representatively have a density of about 3 pounds per lineal foot and as the result of prior tapping have an end portion 8 of cross section reduced in comparison to the generally uniform diameter of the remaining portions of the bar.

The length of bar 3 is designated in FIG. 1 asL Since, as indicated, bar 3 has been derived by reduction through use in tapping of an original bar, it is clear that L, will actually be equal to or greater than the remnant length remaining at "that point in time when an original bar can no longer be safely used for tapping. More specifically this means that L, will be equal to or greater than the minimum safe approach distance to the furnace for an operator using the tapping bars. In a typical furnace of the submerged-arc variety this distance, L will be approximately 6 feet. Bar 5, to which bar 3 is being coupled, may like bar 3 comprise a remnant; but for purposes of concretely illustrating the invention it may be considered that bar 5 is a new bar, exhibiting the normal new length of 20 feet or more. The bars 3 and 5 are seen to be held in abutting relationship at 4 by the sleeve 7. In accordance with the present invention, sleeve 7 comprises a defomtable metallic material of a composition, which like the tapping bars, is innocuous to the furnace and melt and is safely consumable therein, and has adequate strength to function in the manner indicated. Sleeve 7 has an inside diameter only slightly greater than the outside diameter of bars 3 and 5 whereby the latter may be readily inserted into the open ends of sleeve 7 in a simple manual fashion. The wall width of sleeve 7 is, furthermore, preferably not greater than the diameter of bars 3 and 5, whereby effective defonnation thereof can be achieved in a relatively simple manual fashion. Thus, where bars 3 and 5 are of the typical 1- inch diameter referred to, sleeve 7 may comprise a suitable length of carbon steel pipe having an inside diameter of 1.049 in., and an outside diameter of 1.315 in.

In accordance with the present invention, the length, L of sleeve 7 is specifically chosen so as to provide an appropriate rigid support for the assembled bar 3. The significance of the length L is best understood by referring to FIG. 2, wherein the FIG. 1 assembly is shown subsequent to crimping and in use during a tapping operation. As seen in this FIG. 1, the sleeve 7 has now been deformed; e.g. at points 6, to render the assembly completely tight. While sophisticated crimping tools and/or machines may be used to achieve this crimping effect, it is possible, where sleeve 7 possesses the characteristics previously cited, to effect the crimping by simple and direct application of a sledge hammer, or similar implement, to the FIG. 1 assembly. To be able to carry out this operation in such a simple manner is an important consideration, since a single unskilled operator could carry out the required operations for forming assembly 2 directly on the production line quite rapidly.

FIGURE 2 shows schematically the reduced section 8 impinging upon the hardened clay plug 9. In order to breach plug 9, the operator must drive the coupled bars against plug 9 while supporting the bars at an intermediate point. This support point f6 may be an actual mechanical stand, or may simply be the operator's hands. In any event, the distance from point 16 to plug 9 will equal or exceed the dimension L,,, in consequence of which a length, L,;, or greater will be cantilevered from point 16 to plug 9. As operator pressure is applied, it is clear that portion 8 will flex in directions F and F; moreover, the cantilevered portion of bar 3 is at all times subject to stressing from support of its own weight W. Accordingly sleeve 7 should be of sufficient length, L so that adequate distribution along sleeve 7 is possible of the forces producing torque in opposition to the torque from weight W and from those forces acting in directions F and F. Where bar 3 comprises the 1-inch diameter, 6-foot or greater length element, previously cited, having a density of about 3 pounds per lineal foot, it is found that a sleeve length of about 9 inches or more is preferable to achieve optimum assembly rigidity, although lesser lengths can be used, depending upon the specific wall diameter of the sleeve and on the specific plug to be disrupted.

lt may also be observed that sleeve lengths even greater than those cited are preferable where the bar end portions abutting at point 4 are not the flattened ends of original diameter stock, but rather are reduced portions such as at 8. Typically in a situation such as this, where one is thus joining two scrap" sections at their respective reduced ends, it is found that sleeve 7 should have a preferable length of about 18 inches or more.

While the present invention has been particularly described in tenns of specific embodiments, it will be evident that in view of the present disclosure numerous variations upon the invention are possible, which variations will still fall within the true scope of the present teaching. For example, while the invention has been particularly described in connection with an embodiment utilizing only a pair of bars and a single sleeve, a tapping bar assembly having several such joints within its total length is equally possible. Accordingly the invention is to be broadly construed, and limited only by the scope and spirit of the claims now appended hereto.

1 claim:

1. A tapping bar assembly for use in tapping metallurgical furnaces, comprising:

at least a pair of generally cylindrical metal tapping bars held in rigid end to end relationship by a fumace-consumable metallic sleeve surrounding said adjoining ends and crimped about the enclosed portions of said bars.

2. A combination according to claim 1 wherein said sleeve is a deformable pipe.

3. A combination according to claim 1, wherein said sleeve is of sufi'icient length to support at least a 6-foot cantilevered length of one said bar centrally held therein.

4. A combination according to claim 3, wherein said bars are of approximately 1 inch general diameter, and said sleeve is at least 9 inches in length.

5. A combination according to claim 4, wherein the adjoining portions of said bar are reduced below said general 1-inch diameter, and said sleeve is approximately 18 inches in len th. 6. A method for utilizing tapping bars in a metallurgical urnace environment, comprising in sequence the steps of:

a. making a series of taps of said furnace with a first tapping bar, whereby the environment at said tap successively reduces the length of said bar until it is below acceptable tapping length;

b. rigidly coupling said reduced length bar to a second bar to yield a combined bar length adequate for said furnace tapping; and

c. utilizing said coupled bars to effect further taps of said furnace.

7. A method according to claim 6 wherein said bars are coupled by inserting the ends thereof into the open ends of a furnace-consumable metallic sleeve, and crimping said sleeve about said ends to produce said rigid coupling.

8. A method according to claim 7 wherein said crimping is effected by impacting said sleeve with a hand-held hammer. 

1. A tapping bar assembly for use in tapping metallurgical furnaces, comprising: at least a pair of generally cylindrical metal tapping bars held in rigid end to end relationship by a furnace-consumable metallic sleeve surrounding said adjoining ends and crimped about the enclosed portions of said bars.
 2. A combination according to claim 1 wherein said sleeve is a deformable pipe.
 3. A combination according to claim 1, wherein said sleeve is of sufficient length to support at least a 6-foot cantilevered length of one said bar centrally held therein.
 4. A combination according to claim 3, wherein said bars are of approximately 1 inch general diameter, and said sleeve is at least 9 inches in length.
 5. A combination according to claim 4, wherein the adjoining portions of said bar are reduced below said general 1-inch diameter, and said sleeve is approximately 18 inches in length.
 6. A method for utilizing tapping bars in a metallurgical furnace environment, comprising in sequence the steps of: a. making a series of taps of said furnace with a first tapping bar, whereby the environment at said tap successively reduces the length of said bar until it is below acceptable tapping length; b. rigidly coupling said reduced length bar to a second bar to yield a combined bar length adequate for said furnace tapping; and c. utilizing said coupled bars to effect further taps of said furnace.
 7. A method according to claim 6 wherein said bars are coupled by inserting the ends thereof into the open ends of a furnace-consumable metallic sleeve, and crimping said sleeve about said ends to produce said rigid coupling.
 8. A method according to claim 7 wherein said crimping is effected by impacting said sleeve with a hand-held hammer. 